XF86Display duplicated keycode each keypress

[João Gabriel Reis]

Hello, I'm trying to map the XF86Display key (fn + F1) to a script, my
problem is that everytime I press the key, the script is executed
twice. I checked the keycode with the showkey command and I get this
when the key is pressed:

keycode 227 press
keycode 227 release
keycode 227 press
keycode 227 release

Seems that the key is interpreted twice, this is normal? Shouldn't
just be one time? My laptop is a Dell Inspiron 1545, here's the output
of setxkbmap -print -verbose 10:

setxkbmap -print -verbose 10

Setting verbose level to 10
locale is C
Applied rules from evdev:
model:      evdev
layout:     br
variant:    abnt2
Trying to build keymap using the following components:
keycodes:   evdev+aliases(qwerty)
types:      complete
compat:     complete
symbols:    pc+br(abnt2)+inet(evdev)
geometry:   pc(pc104)
xkb_keymap {
    xkb_keycodes  { include "evdev+aliases(qwerty)"    };
    xkb_types     { include "complete"    };
    xkb_compat    { include "complete"    };
    xkb_symbols   { include "pc+br(abnt2)+inet(evdev)"    };
    xkb_geometry  { include "pc(pc104)"    };
};